How hard was it to replace the thermostat? Did you use a gasket or a silicone sealant?

 

Easier than I thought. Took me all of one hour and I only had to remove the intake air hose to get to it. I used a gasket with some silicone sealer.

 

Well, that DID NOT solve the problem. Same place, same time as always, she did it again last night. Lost about 1/2 gallon of antifreeze as normal when this happens. I knew something was going to happen when the gauge went from normal to cold in a matter of 5 seconds then 10 seconds later, all the way to hot for about 1/2 mile then back to normal.

I checked the reservoir and found a nice surprise, a nice orangish "pond scum" floating on the top. I am noticing this (as before the original flush) orange tint in the antifreeze also. So something is leaking into something else. Checked the oil and found no water/antifreeze in it.

I was going to trade this truck off in the spring but I might do that sooner than later with how this truck is playing with me. The head gaskets look like a 2-3 day job with the capabilities I have and I can't afford to have anyone else do it. On top of that who knows if the block or heads aren't warped. This is getting aggravating.

 

To check for exhaust leaks into the cooling system, drain the system until the coolant level stands just above the top of the cylinder heads, then disconnect the radiator upper hose and remove the thermostat and fan belt. Start the engine and quickly accelerate several times. At the same time note any appreciable coolant rise or the appearance of bubbles which are indicative of exhaust gases leaking into the cooling system.

 

I'll give it a shot when it's not raining outside. Either way the truck will probably go bye bye since I have been wanting to do it for a couple years now. My guess is exhaust is leaking into the coolant system thus making an air bubble and overheating the truck until it boils enough coolant out to bypass the temp sensor or something along those lines.

 

It sounds more like the Burmuda triangle if you ask me ha ha.

 

A little update.

I installed the new thermostat. Found out it was put in backwards (my stupid mistake, thought the old one was in like that.) The above overheat problem happened once and it never happened again. The truck temp gauge did act weird after that as in it would bounce around for a long time before finally resting in the middle. If you hit a fast paced road, it would drop to cold and slowly climb. I figured it wasn't hurting anything more than it was before and left it for a month until I could find time to swap it back to the right position.

Today I finally put the bulb part facing down and filled it to the top of the radiator with antifreeze. Tonight, I made it one mile before the gauge and heater went cold and the famous overheating cycle begun. When I get paid I'm going to buy a compression checker and check it myself. Something is leaking somewhere because the orange slime now infesting my reservoir smells very oily/gassy.

I would love to just drop another engine in the truck but I am alone here and don't have a cherry picker or the $1k for a complete setup ready to go. It's so frustrating.